Description

Designed for the accurate measurement and control of process steam for end-of-the-run applications: steam injection to process ovens, atmospheric blanchers, sparging tanks, direct steam to product tanks, and other applications where steam is exhausted through a pipe manifold or nozzles to near atmospheric pressure.

The steam flow rate transmitter will supply an analog output signal suitable for driving remote digital indicators, chart recorders, or closing the loop to a process controller. Analog output signals may be specified as 0-5VDC, 4-20mA, or 0-20mA. A pressure transducer with additional signal conditioning electronics is packaged within the transmitter housing to provide a linear signal proportional to mass flow rate over the full rate range. Mass flow rate is metered from zero flow to full scale capacity. In addition, a calibrated panel gauge is included for local indication of the steam flow rate.

Electrical connections are made through a watertight connector on the enclosure. Control power and signal wires connect to numbered screws inside the connector cover. The connector will thread to liquid-tight electrical conduit.

Installed in series with the steam piping, the transmitter is inherently simple and rugged. There are no moving parts to maintain or replace. There are no obstructions in the steam flow path.

Principle of Operation

Principle of Operation

The steam flow rate transmitter does NOT require calibration at a fixed upstream operating pressure. Differential pressure is NOT measured. Mass flow rate is strictly proportional to the pressure at the inlet of the critical flow venturi.

For the system to operate correctly, a small pressure drop across the nozzle is required. The proprietary design is such that the exit pressure may be as high as 90% of the inlet pressure for acceptable operation. Steam to atmosphere and open tank applications easily meet these operating conditions.

Configuration

The transmitter is an in-line device which will operate in any flow orientation. If desired, the transmitter may be reconfigured in the field to a different flow direction.

The steam flow rate is controlled by throttling on the inlet side of the transmitter. Manual and specialty control valves, or pressure regulators may be used as pressure reducing devices.

When required, non-standard capacities, special construction, or other optional features can be provided.

Specifications

Rated Pressure

150 PSIG Max.

Ambient Temperature

40°F to 140°F

Absolute Pressure Ratio (Exit to Inlet)

90% Max.

Analog Output Signals

0-5VDC, 1-5VDC, 4-20mA, 0-20mA

Power

24VDC Nominal, 50mA Max.

Accuracy

±5 F.S.

Ordering Information

Steam flow rate transmitters are described by indicating the following combination of product features.